ROGALLA, S. V. A. N. A.SHAWKEY, M. A. T. T. H. E. W. D.D'ALBA, L. I. L. I. A. N. A.
16页查看更多>>摘要：Plumage coloration can have substantial effects on a bird's energy budget. This is because different colours reflect and absorb light differently, affecting the heat loads acquired from solar radiation. We examine the thermal effects of feather coloration on solar heat gain and flight performance and discuss the potential role of plumage colour on a bird's energy budget. Early investigations of the effects of plumage colour on thermoregulation revealed complex interactions between environmental conditions and physical properties of the plumage that may have led to diverse behavioural and physiological adaptations of birds to their thermal environment. While darker feather surfaces absorb more light, and heat more, than light-coloured surfaces under exposure to the sun, this relationship is not always straightforward when considering heat transfer to the skin. Heat transfer through plumage varies depending on multiple factors, such as feather density and transmission of light. For instance, higher transmissivity of light-coloured plumage can increase heat loads reaching skin level, while conduction and convection transfer heat from the surface of dark feathers to the skin. Solar heating can affect the metabolic costs of maintaining a constant body temperature, and depending on environmental conditions, colours can have either a positive or negative effect on a bird's energy budget. More specifically, solar heating can be advantageous in the cold but may increase the energetic costs associated with thermoregulation when ambient temperature is high. More recent studies have further suggested that the thermal properties of feather coloration might reduce the energetic costs of flight. This is because surface heating can affect the ratio between lift and drag on a wing. As concluding remarks, we provide future directions for new lines of research that will aid in improving our understanding of the thermal effects of feather coloration on a bird's energy budget, which can potentially explain factors driving colour evolution and distribution patterns in birds.
原文链接:
NSTL
Wiley
Mcdonald, Grant C.Bede-Fazekas, AkosIvanov, AntonCrecco, Lorenzo...
19页查看更多>>摘要：Worldwide populations of shorebirds are declining, associated with a complex interplay of climate change, predation, human disturbance and habitat degradation. Comprehensive information on the distribution and breeding ecology of shorebird populations is crucial to understand and mitigate these threats. Kazakhstan, the largest country in Central Asia, comprises multiple flyways and breeding habitats for shorebird species, including the Kentish Plover Charadrius alexandrinus, but information on the population size and breeding distribution of shorebird species in the region is highly limited. We conducted a wide-scale survey of Kentish Plover across Kazakhstan during the breeding season and utilize species distribution modelling to outline key anthropogenic and environmental variables that determine Kentish Plover presence. Our results reveal widespread distribution of Kentish Plovers across Kazakhstan but indicate that breeding densities are generally low. Our distribution modelling stresses the primary importance of proximity to water bodies and climate as the main predictors of Kentish Plover presence, but reveals a weak association with indicators of human disturbance. We utilize our distribution modelling to provide the first quantitative estimate of the breeding population size of Kentish Plover in Kazakhstan, which indicates a modest number of individuals given the size of the country (between 12 000 and 32 000 individuals). Our results indicate the key routes via which climate change may impact on population-level distributions of Kentish Plover and provide a platform for future studies investigating species distributions across similarly vast and inaccessible regions.
原文链接:- NSTL
- Wiley
Rolek, Brian W.Braham, Melissa A.Miller, Tricia A.Duerr, Adam E....
13页查看更多>>摘要：Operators of wind power facilities can mitigate wildlife mortality by slowing or stopping wind turbines (hereafter 'curtail') when birds are at an increased risk of collision. Some facility operators curtail when individual birds have flight characteristics (e.g. altitude, distance or relative bearing of a bird's flight path) that exceed some threshold value, but thresholds currently in use have not been empirically evaluated. Overly restrictive thresholds can cause turbine curtailment for birds that never enter rotor-swept zones, thereby resulting in excess power loss. We evaluated the probability that birds, specifically eagles, entered the rotor-swept zone (hereafter 'entry probability') in response to their flight characteristics. We used an automated monitoring system to classify individuals as eagles or non-eagles and record flight paths of purported eagles at a wind facility in Wyoming, USA. We used logistic regression with occupancy dynamics and a distance-dependent colonization process to model entry probability. As a result, this model allowed entry probability to decrease with horizontal distance to the nearest turbine. The probability of entry varied with distance to the nearest turbine and approached zero when that distance was more than 202 m. Entry probability peaked when eagles flew 89 m above ground, corresponding to hub heights of turbines (80 m), and decreased to near-zero at altitudes of 189 m or more. Entry probabilities were greatest when flight paths were near the rotor-swept zone and when eagles flew slowly toward the nearest turbine. Compass bearing of a flight path was not associated with entry probability. Our model accurately forecasted entry probability in Wyoming (area under the curve (AUC) = 0.96) and was transferable to another facility in California, USA (AUC = 0.97); therefore, our results may be applicable across a variety of settings. Curtailment criteria can be based on flight path characteristics to forecast entry into rotor-swept zones. The use of distance and altitude thresholds when making curtailment decisions is justified. However, this analysis suggests alteration of the time to collision threshold, with curtailment initiated at greater distances as the speed of the bird decreases. Our novel modelling method and our results can inform curtailment criteria in any situation where curtailment decisions are made in real-time.
原文链接:- NSTL
- Wiley
Cibois, AliceBeaud, MichelFoletti, FrancescoGory, Gerard...
17页查看更多>>摘要：Artificial structures, and particularly in urban settings, attract species showing similar ecological niches and provide nest-sites for cavity-breeding species. It is, however, unknown whether this proximity creates opportunities for hybridization and gene flow across related species. We investigated whether two colonial species, the Common Swift Apus apus and the Pallid Swift Apus pallidus, are experiencing gene flow by genotyping individuals that breed in sympatry in the town of Bastia (Corsica, France). We compared them with individuals sampled in colonies where a single species is breeding, in the Mediterranean region and in Switzerland. Our results provided evidence of gene flow between the two species and showed that introgression was not limited to sympatric urban colonies. Gene flow was asymmetrical, with more Pallid Swifts than Common Swifts showing evidence of mixed ancestry. Several individuals were assessed as late-generation hybrids, suggesting that introgression between the two species was associated with their range expansion since the Last Glacial Maximum. However, we also identified individuals that exhibit the characteristics of recent-generation hybrids, particularly in Bastia. This result suggests that hybridization between the two species is an ongoing and underestimated phenomenon, with a single observation of a mixed pair in the literature, and may be favoured by close proximity in urban colonies.
原文链接:- NSTL
- Wiley
Carvalho, Paloma C.Ronconi, Robert A.Bugoni, LeandroDavoren, Gail K....
15页查看更多>>摘要：Moult is an energetically demanding period, during which flight may be impaired and foraging ranges may become constrained. During the non-breeding period, Great Ardenna gravis and Sooty Ardenna grisea Shearwaters migrate from South Atlantic breeding colonies to aggregate at North Atlantic feeding grounds. We investigated whether both shearwater species used coastal Newfoundland, Canada, as a moulting area and used stable isotope ratios (delta N-15, delta C-13) of recently moulted primary feathers (P1, P5, P10) to infer moult location/diet for both species. Moult scores indicated that both species finished their moult (i.e. P6-10) in coastal Newfoundland, which was further corroborated with similar stable isotope ratios for Great (delta N-15 = 15.17 +/- 1.13 parts per thousand; delta C-13 = -18.66 +/- 0.54 parts per thousand) and Sooty Shearwaters (15.54 +/- 0.74 parts per thousand; -18.43 +/- 0.78 parts per thousand); however, Sooty Shearwater moult was more advanced relative to that of Great Shearwater. In contrast, isotopic ratios of P1 and P5, which were grown before arriving in coastal Newfoundland, differed between and within species, suggesting divergent locations/diet during early moult. For Great Shearwaters, P1/P5 isotopic ratios were more variable (broader niche breadth) than P10, suggesting that some individuals started moulting in the South Atlantic prior to trans-equatorial migration, whereas others start moulting in the North Atlantic Ocean. Sooty Shearwaters had two distinct groupings of either higher or lower delta N-15 in P1/P5, suggesting that individuals began moulting either on the Newfoundland Shelf or further offshore based on comparisons to reference shearwater feathers grown in known locations. These findings illustrate distinct locations and/or diets at the start of primary feather moult, both within and between species, but diets converged when aggregated together at the end of moult in coastal North America, where growing feathers of both species were sampled. More importantly, we identified an important area for both Sooty and Great Shearwaters to complete their moult in coastal Newfoundland. Protecting this moulting area would minimize disturbance and the impacts of threats (e.g. by-catch) to both species during this energetically demanding period. The area has been suggested previously to be an important candidate area for protection due to annually persistent prey aggregations that can be spatiotemporally delimited based on specific prey habitat requirements.
原文链接:- NSTL
- Wiley
BULLA, M. A. R. T. I. N.MUCK, C. H. R. I. S. T. I. N. A.TRITSCHER, D. A. N. I. E. L. A.KEMPENAERS, B. A. R. T....
22页查看更多>>摘要：In species with biparental care, coordination of parental behaviour between pair members increases reproductive success. Coordination is difficult if opportunities to communicate are scarce, which might have led to the evolution of elaborate nest relief rituals in species facing a low predation risk. However, whether such conspicuous rituals also evolved in species that avoid predation by relying on crypsis remains unclear. Here, we used a continuous monitoring system to describe nest relief behaviour during incubation in an Arctic-breeding shorebird with passive nest defence, the Semipalmated Sandpiper Calidris pusilla. We also explored whether behaviour of exchanging parents informs about parental coordination and predicts incubation effort. We found that incubating parents vocalized twice as much before the arrival of their partner than during other times of incubation. In at least 75% of exchanges, the incubating parent left the nest only after its partner had returned and initiated the nest relief. In these cases, exchanges were quick (25 s, median) and shortened over the incubation period by 0.1-1.4 s/day (95% CI), suggesting that parents became more synchronized. However, nest reliefs were not cryptic. In 90% of exchanges, at least one parent vocalized, and in 20% of nest reliefs the incubating parent left the nest only after its returning partner called incessantly. In 27% of cases, the returning parent initiated the nest relief with a call; in 39% of these cases, the incubating partner replied. If the partner replied, its following off-nest bout was 1-4 h (95% CI) longer than when the partner did not reply, which corresponds to an 8-45% increase. Our results indicate that incubating Semipalmated Sandpipers, which rely on crypsis to avoid nest predation, have quick but acoustically conspicuous nest reliefs. Our results also suggest that vocalizations during nest reliefs may be important for the coordination and division of parental duties.
原文链接:- NSTL
- Wiley
Berris, Karleah K.Barth, MichaelMooney, Trish
14页查看更多>>摘要：Nestboxes have been deployed for parrots and cockatoos (Psittaciformes) worldwide, but there is limited evidence of their efficacy for these species. We examined the use of nestboxes by endangered South Australian Glossy Black Cockatoos Calyptorhynchus lathami halmaturinus, a habitat specialist that feeds almost solely on the seeds of Drooping Sheoak Allocasuarina verticillata trees, and investigated the factors that influenced nestbox use. Between 1998 and 2017, the mean annual proportion of nesting attempts that successfully fledged a chick was similar in nestboxes (52%, n = 547) and natural hollows (53%, n = 627). Nestbox use increased over time, which may reflect changes in the size and extent of the Glossy Black Cockatoo population over the study period. Nestboxes were more likely to be used by Glossy Black Cockatoos if they were close to the nest of another breeding pair and were not occupied by Yellow-tailed Black Cockatoos Zanda funerea early in the breeding season. Nestboxes were also more likely to be used if they had been used in the previous breeding season, indicating nest-site fidelity. The amount of A. verticillata feeding habitat in a 1-km and 5-km radius did not significantly influence nestbox use. Our study provides further evidence of the value of nestboxes to cockatoo conservation programmes, but also suggests that multiple factors other than local food availability influence uptake by a target species. Given that Glossy Black Cockatoos prefer to aggregate their nests, nestboxes for this species are most likely to be beneficial when they are used to expand the capacity of existing breeding areas or are clustered in the landscape. Our study demonstrates that well-designed nestbox deployments should consider the preferred social groupings of cockatoos during the breeding season, and the location of competitor species, in order to maximize nestbox uptake.
原文链接:- NSTL
- Wiley
Nicolas, LeticiaTorres, RoxanaMontoya, BibianaHernandez, America...
14页查看更多>>摘要：The environmental stressors that females face before egg-laying, such as competition for resources, can impact the fitness prospects of the female as well as her offspring through hormone-mediated maternal effects. In obligate secondary cavity-nesting species, suitable nest-holes are a limited resource, so gaining access to nest-sites may require competition with other individuals. In the Western Bluebird Sialia mexicana, we experimentally evaluated whether female exposure to increased competition for nest cavities (reduced available nest-holes plus exposure to a competitor's decoy and vocalizations) during the period of nest construction affects her offspring's developmental trajectory, survival probability and behaviour through an increase in the concentration of testosterone in the egg yolk. Chicks from experimental females had a lower body mass at age 3 days, followed by a faster growth rate during the rapid growth phase, a slower growth rate during the slow growth phase and larger tarsus at age 15 days (only male offspring). Additionally, experimental chicks exhibited a lower breathing rate. However, female exposure to stronger competition for nest cavities during nest construction did not affect testosterone concentration in the egg yolk. Differential testosterone deposition in yolk is therefore apparently not the underlying mechanism of the effects observed, which may be attributed to changes in females' parental behaviour triggered by competition for breeding sites.
原文链接:- NSTL
- Wiley
Gameiro, JoaoCatry, TeresaMarcelino, JoanaFranco, Aldina M. A....
13页查看更多>>摘要：Although successful at recovering endangered populations, conservation actions based on nest provisioning seldom consider how they shape the composition of communities and alter interspecific interactions. Specifically, the extent to which dietary overlap within these communities may affect the conservation of target species has rarely been assessed. In Southern Europe, sites of large-scale nest-site provisioning aimed at recovering Lesser Kestrels Falco naumanni populations have attracted non-target bird species, resulting in mixed breeding assemblages that might promote interspecific competition for resources during breeding. Here we used stable isotope analysis (delta N-15 and delta C-13) to assess inter- and intraspecific dietary segregation in these assemblages and investigate the mechanisms allowing species coexistence. We examined resource partitioning and trophic niche overlap among Lesser Kestrels, Common Kestrels Falco tinnunculus, European Rollers Coracias garrulus, Western Barn Owls Tyto alba, Little Owls Athene noctua and Spotless Starlings Sturnus unicolor; and within species between parents and their offspring. Similar isotope ratios and highly overlapped niches, particularly among Lesser Kestrels, Rollers and Starlings, suggest limited dietary segregation and use of similar prey. Within species, parent-offspring segregation was marked across all species. Our results indicate that species breeding in these assemblages occupy similar ecological niches, despite a potential increase in competition. High resource availability in the area may permit coexistence but the viability of mixed-species groups may be compromised in areas with limited resources, which are predicted to expand with ongoing human- and climate-induced changes. Conservation practices based on nest provisioning should consider the ecological niches of target and non-target species as well as their interactions.
原文链接:- NSTL
- Wiley
